Isocyanatosulfur and isothiocyanato-sulfur pentafluorides and their preparation



vone of the reactants invention, may be prepared by reacting sulfur chloride United States Patent ABSTRACT OF THE DISCLOSURE Claimed are the compounds SF NCO and SF NCS,

.the first useful as a water repellant and the second as a solvent. They may be prepared by reacting SF NHCF with a carboxylic or carbothiolic acidin the presence of an alkali metal fluoride.

This invention relates to, and has as its principal objects provision of. two novel and useful compounds containing the SP function and methods for the preparation of the same.

Field of the invention Summary and details of the invention The two novel compounds of this invention are isocyanatosulfur pentafluoride and isothiocyanatosulfur pentafluoride, i.e., the compounds of the formula SF NCX where X is oxygen or sulfur. A first method ofpreparing these compounds is by reacting (dichloromethylene amino)sulfur pentafluoride, SF N=CCl or (difluoromethyleneamino)sulfur pentafluoride, SF N=CF with water or hydrogen sulfide (H X), respectively. A second, alternative, method of preparing the compounds is by reacting (trifluoromethylamino)sulfur pentafluoride with a carboxylic or carbothiolic acid and an alkali metal fluoride.

In accomplishing the first method for. making the present novel compounds, a pressure reactor is conveniently charged with H X and either CF N=CCI or SFN =CF the reactor is closed, and the charge heated to a temperature of up to 150 C. The reaction mixture is thereafter allowed to cool to ambient temperature and the desired reaction product is isolated by distillation or other means known to those 'skilled in the art. The reaction of this processtof the invention can be illustrated by the equations (SF N=CCl only is shown for the sake of (Dichloromethyleneamino)sulfur pentafluoride,

SF N=CCl g usable in the first process of the pentafluoride, SF CI, with cyanogen chloride, ClCN, in the presence of ultraviolet light, as described below:

A 12-liter round-bottom flask containing 14 g. of cyanogen chloride and 37 g. of sulfur chloride pentafluoride,

SF CI, was irradiated for 6.5 hours at ambient temperature. The contents were then removed and allowed to sponded to a 38% conversion, based on SF Cl, of colorless SF N=CCl B.P. 8688 C. The foreshot, B.P. 35- 86 C., amounting to 6.4 g. was SF N=CCl contaminated with a small amount of 5 F The product (dichloromethyleneamino)sulfur pentafluoride, SF N=CCl reacted with 10% sodium hydroxide solution to give a solution containing both chloride and fluoride ions.

Analysis.Calcd. for CCl F NS: Cl, 31.70; F, 42.41; S, 14.28. Found: Cl, 32.37; F, 42.44; S, 13.63.

The F n-m-r spectrum indicated that an SP group was present. The infrared spectrum showed absorption at 6.1014 (C=N) and in the 10.5 to 120; region (SP Mass spectrometric analysis was satisfactory. Peaks corresponding to the parent (223), to SP (127), and to C01 (82) were found to be present. The alternate structure for this compound, SF CCl=NCl, was eliminated when hydrogen fluoride was found to convert it to SF NHCF and sodium fluoride was found to convert it to SF5N=CF2.

(Difluoromethyleneamino)sulfur pentafluoride,

is prepared by reacting (dichloromethyleneamino)sulfur pentafluoride with an alkali metal fluoride in the presence of a suitable reaction medium, e.g., tetramethylene sulfone, as described below:

To a suspension of 25 g. of sodium fluoride in 50 ml. of tetramethylene sulfone was added 17.8 g. of SF N=CCl at ambient temperature. The contents were rapidly heated to C. and then at 75-156 C. for 0.75 hour, during which time the volatile products removed were collected in a solid carbon dioxide-acetone cooled trap. The volatile material thus obtained was combined with that from a second experiment using 24 g. of SF N=CCl Distillation of the composite yielded 6 g., B.P. 5-9 C. (I), and 12 g., B.P. 912.5 C. (II). Mass spectrometric analysis of II was satisfactory for SF N=CF (difluoromethyleneamino)sulfur pentafluoride, with the highest mass being the parent peak (211). The F n-m-r spectrum showed the presence of an SP and a CF group. Infrared analysis showed absorption at 5.58;]. C=N), at 7.45 and 7.60 1. (C-F), and in the 11 to 12,11 region (SP Infrared analysis also showed that cut I also was -90% SF N=CF therefore, the product was obtained in about a 45% conversion.

Analysis.-Calcd. for CF NSt F, 69.63; S, 16.75. Found: F, 68.50; S, 16.98.

The temperatures used in the reaction of SF N=CCI or SF N=CF with water or hydrogen sulfide can vary from 25 to 150 C. but generally are from 70 to 125 C.

When water is used as the reactant, the reaction can be conducted in open or closed reactors under autogenous pressure. The use of excess water is to be avoided since water hydrolyzes SF NCO.

When hydrogen sulfide is used, the reaction is conducted in a closed reactor under autogenous pressure conditions. If desired, however, externally applied pressure, sufiicient to maintain the hydrogen sulfide in the liquid state, can be used. Excess hydrogen sulfide can be used in the reaction with SF N=CCl or SF N CF particularly in reactions carried out below C. However, in reactions of SF N=CCI or SF N=CF with hydrogen sulfide in the presence of added sodium fluoride (added to absorb hydrogen fluoride and/or hydrogen chloride) the use of excess hydrogen sulfide is detrimental.

If desired, a reaction medium, other than the H X compound, can be used. When such a medium is used,

an alkali metal fluoride, and a carboxylic acid, RCO H, or a carbothiolic acid,

where R is alkyl, preferably of up to 18 carbons, or aryl, preferably of up to 11 carbons, closed, and the charge is then heated under autogeneous pressure, for from 15 minutes to four hours at temperatures up to 150 C. Thereafter the charge is permitted to cool, the reactor is opened, and the contents discharged. The desired reaction product is recovered from the reaction mixture by distillation, or other method known to those skilled in the art. This reaction involves one mole of (trifiuoromethylamino)sulfur pentafiuoride, two moles of alkali metal fluoride, and one mole of carboxylic or carbothiolic acid, in accord with the equations:

(Trifluoromethylamino) sulfur pentafiuoride,

SF NHCF is prepared by reacting (dichloromethyleneamino)sulfur pentafluoride with hydrogen fluoride, HF, under autogenous pressure, as described below:

A mixture of 23 g. of SF N=CCl and 23 g. of hydrogen fluoride was heated at 70-80" C. for two hours, under autogeneous pressure, and then stored over sodium fluoride at room temperature and autogeneous pressure to remove hydrogen chloride and unreacted hydrogen fluoride. Distillation of the product yielded 14.7 g., amounting to a 68% conversion, of SF NHCF (trifluoromethylamino)sulfur pentafiuoride, B.P. 28.5 to 31 C., and 1.9 g. of a product with a B.P. 31.5 to 34 C. Mass spectrometric analysis showed a peak corresponding to the parent (211) and lower mass fragments which supported the (trifluoromethylamino)sulfur pentafluoride structure. The infrared spectrum showed absorption at 2.88 and 6.80m (NH), at 8.38 (CF), and at 10.97 and 11.43 (SP The F n-m-r spectrum indicated that an SP and a CF group were present.

Analysis.-Calcd. for CHF NS: F, 72.04; S, 15.17. Found1F, 71.78;S, 15.91.

The alkali metal fluorides usable are those of sodium, potassium, rubidium, and cesium. Of these, sodium fluoride is preferred because of its effectiveness, relatively low cost and availability. The amount of alkali metal fluoride employed is at least two moles per mole of (trifluoromethylamino) sulfur pentafluoride in the charge.

The canboxylic or carbothiolic acid reactant can be any alkanoic carboxylic or carbothiolic acid but the preferred acids are those which contain no more than 18 carbon atoms. The acid reactant can also be any aryl carboxylic or aryl canbothiolic acid but the preferred such carboxylic acids are the monocarboxylic acids of up to 11' carbon atoms. Exemplary of acids of the above kinds are acetic, propionic, .butyric, octanoic, dodecanoic, octadecanoic, thiolacetic, thiolpropionic, thiol butyric, thiolhexanoic,

thioloctanoic, thioldecanoic, JlJCIlZOlC, toluic, naphthalene canboxylic, thiolbenzoic, thioltoluic, and the like.

The acid is employed in'amount which is the molar equivalent of the (trifluoromethylamino)sulfur pentafiuoride. A larger amount of acid can be used, if desired, and the excess recovered for reuse after the reaction is complete.

The reaction between the SF NHCF alkali metal fluoride, and carboxylic or carbothiolic acid is usually carried out in a closed reactor under autogeneous pressure at temperatures which can vary from to 250 C. but are generally held in the range of to 225 C.

The time of reaction in both the first and second processes described above can vary from a few minutes up to six hours. 1

Isocyanatosulfur pentafiuoride, SF NCO, and isothiocyanatosulfur pentafiuoride, SF NCS, react with alcohols to form urethanes and with hydroxyl-containing and secondary amide group-containing polymers to form polymers having modified properties.

Embodiments of the invention The examples which follow are submitted to illustrate and not to limit this invention.

A mixture of 88 g. of benzoic acid, 103 g. of sodium fluoride, and 129 g. of (trifluoromethylamino)sulfur pentafiuoride, SF NHCF were heated at 100 C. for one hour, and then 200 C. for one hour, under autogenous pressures in a 500 ml. Hastelloy C pressure reactor. The 81 g. of volatile product recovered on distillation yielded 11 g. of foreshot, B.P. 39 to 0 C. and 61 g. (amounting to a 79% conversion) of SF NCO, B.P. 5.0 to 55 C. Infrared analysis of the foreshot indicated it was 65% SF NCO and 25% SO F with a small amount of SOF The infrared analysis showed strong absorption at 4.4, for NCO and strong absorption in the 11-12p. region for SP Mass spectrometric analysis was satisfactory for SF NCO, and showed peaks corresponding to the parent (169), to the parent minus fluorine (150), to SP (-127), to SE, (89), and to COF (47).

The F nuclear magnetic resonance spectrum at 56.4 m.c.p.s. standardized against CCl F-CCl F showed the following peaks (in c.p.s.), all on the minus side: 8670, 8656, 8515 and the following nine smaller peaks: 7890, 7755, 7705, 7620, 7595, 7550', 7455, 7420, and 7300.

Analysis.Calcd. for CF NOS: F, 56.21; S, 18.93. Found: F, 56.37; S, 18.99.

(B) Isocyanatosulfur pentafiuoride, SF NCO, reacts with hydroxyl group-containing compounds to form urethanes, as exemplified below:

A mixture of 15 g. of SF NCO, prepared as above, 9.6 g. of benzyl alcohol, and 20 ml. of carbon tetrachloride was allowed to stand at 25 C. and autogenous pressure over the weekend, then warmed at 90 C. for two hours. The 20 g. of white solid (amounting to an 81% conversion) recovered was dissolved in ml. of hot carbon tetrachloride and the solution allowed to cool to room temperature, whereupon there was obtained nearly quantitative recovery of SF NHCO CH C H M.P. 101-102 C. The infrared spectrum (nujol mull) showed, in addition to the nujol peaks, absorption at 3.0a (NH), at 5.7 to 5.8 ((3:0), and broad absorption in the 11-12 region (SP Analysis.-Calcd. for C H F NO S: C, 34.66; H, 2.89; F, 34.30. Found: C, 34.83; H, 2.61; F, 34.01.

A test portion of the product was suspended in water at 25 C. for 17 hours without reaction or fluoride ion formation. The preparation of this derivative of SF NCO provided further experimental data for its structure.

(A) A mixture of 59 g. of SF N CCl and 59 g. of hydrogen sulfide Was heated at 80 C. for two hours and autogenous pressure in a 500 ml. Hastelloy C pressure reactor. After storage over sodium fluoride pellets, the crude product yielded on distillation, 49 g. of H 8, B.P. -52 C., 3.4 g. (7% conversion) of SF NCS, B.P. 4748 C., and 48 g. of unreacted SF N:CCl B.P. 83.5-88.5 C. The infrared spectrum of the SF NCS showed absorption at 5.12;]. (NCS) and strong absorption at 1097a (SP The F nuclear magnetic resonance spectrum at 56.4 m.c.p.s. showed the presence of an SE group. Mass spectrometric analysis was satisfactory, showing a peak corresponding to the parent (185) and lower mass fragments which supported the SF NCS structure.

Analysis.Calcd. for CF NS F, 51.35; S, 34.59. Found: F, 51.06; S, 34.28.

(B) In another experiment in which 45 g. of SF N CCl 25 g. of hydrogen sulfide, and 50 g. of sodium fluoride were heated at 75 C. for one hour and 125 C. for two hours, distillation of the liquid product yielded the following cuts:

Cut N0. Boiling Point Wt. (g Products 22. 5-37 1. 7 CS SF5NHCF3, SF NCS 37-39 5.2 1.50 mole Percent SF5NCS; 3940 3. 2 (50 mole Percent CS2. 42-44. 3 6. 4 80 mole percent SF NCS;

mole percent CS2.

Infrared analyses of the fractions indicated that SF NCS was obtained in about a conversion. On cooling, a sample containing SF NCS and CS to 1 0 to 20 C., two layers separated indicating that the SF NCS can be separated from the CS in this manner.

This experiment suggests that it would be desirable not to use an excess of hydrogen sulfide since it reacts with SF N=CCl particularly in the presence of sodium fluoride.

EXAMPLE III SF5NHCF3 2NaF 0011500811 Cut No. Boiling Wt. (g.) Product Point, 0. (mole percent) SF NOS 1 2635 9.5 SF NCO (10) SF NHCF3 2 3&45 1 7 {SF5NCS SFsNHCFs (30) 3 45-50 5. 4 SF NOS Residue=l.7 g.; volatiles collected in trap during distillation=0.8 g. (2.9 g. loss during distillation). Infrared an- 6 alysis showed out No. 3 to be chiefly SF NCS. The overall conversion to SF NCS, based on SF NHCF was about 35%.

The compound SF NCS has been found to be a solvent for low molecular weight polytetrafluoroethylene. The solutions thus obtained can be applied to fibrous materials such as paper, fabrics, wood, etc., to impart fire-retardant and water-repellent properties.

The compound SF NCO has been used to impart water repellency to cotton cloth. For example, cotton broadcloth (5.87 g.) was heated with 18 g. of SF NCO at C. for two hours and autogenous pressure. This resulted in a 7% weight gain of the cloth. The surface appeared to be somewhat unevenly modified with a white precipitate; this probably resulted fom the fact that the cloth was folded to get it into the bomb. Drops of water were placed on samples of the treated and untreated cloth, and the time for the absorption of the droplet of water noted (this is really the time for wet-through of the cloth).

Time for wet-through, seconds:

Untreated cloth 23 Treated cloth l20 360 Since obvious modifications and equivalents in the invention will be evident to those skilled in the chemical arts, I propose to be bound solely by the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

I claim:

1. Compounds having the formula SF NCX wherein X is selected from the group consisting of oxygen and sulfur.

2. Isocyanatosulfur pentafluoride SF NCO.

v3. Isothiocyanatosulfur pentafluoride of the formula SF NCS.

-4. The process of preparing the compounds of claim 1 which comprises reacting SF NHCF and a member of the group consisting of carboxylic acids of the formula RCOOH, R being alkyl or aryl, and carbothiolic acids of the formula RCOSH, R being as above, in the presence of an alkali metal fluoride.

5. The process of claim 4 wherein the alkali metal fluoride is sodium fluoride.

6. The process of preparing the compound of claim 2 which comprises reacting SF NHCF with benzoic acid in the presence of an alkali metal fluoride.

7. The process of claim 6 wherein the alkali metal fluoride is sodium fluoride.

8. The process of preparing the compound of claim 3 which comprises reacting SF NHCF with thiolbenzoic acid in the presence of an alkali metal fluoride.

9. The process of claim 8 wherein the alkali metal fluoride is sodium fluoride.

of the formula References Cited UNITED STATES PATENTS 3,228,981 1/1966 Tullock 260543 OTHER REFERENCES Meldrum et al.: Introduction To Theoretical Chemistry, 1936, pp. 122424.

Attaway et al.: Journal Of The American Chemical Society, volume 81, pages 3599-3603 (July 20, 1959).

Moeller: Inorganic Chemistry, 1952, pages 463-466.

MILTON WEISSMAN, Primary Examiner. MAURICE A. BRINDISI, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,547 ,644 October 17 1967 Charles W. Tullock It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 25, strike out "Field of the invention", in ,talics, and insert the same before line 20 as a heading; line 2, for "CF N=CCl read SF N=CCl same line 42, for SFN =CF read SF N=CF column 5, in the first table, ourth column, line 1 thereof, for "CS read CS Signed and sealed this 26th day of November 1968.

EAL)

vard M. Fletcher, J r. EDWARD J. BRENNER esting Officer Commissioner of Patents 

1. COMPOUNDS HAVING THE FORMULA SF5NCX WHEREIN X IS SELECTED FROM THE GROUP CONSISTING OF OXYGEN AND SULFUR.
 4. THE PROCESS OF PREPARING THE COMPOUNDS OF CLAIM 1 WHICH COMPRISES REACTING SF5NHCF3 AND A MEMBER OF THE GROUP CONSISTING OF CARBOXYLIC ACIDS OF THE FORMULA RCOOH, R BEING ALKYL OR ALKYL OR ARYL, AND CARBOTHIOLIC ACIDS OF THE FORMULA RCOSH, R BEING AS ABOVE, IN THE PRESENCE OF AN ALKALI METAL FLUORIDE. 